These experiments were performed in an attempt to see if atheroma have different spectroscopic characteristics than normal human aorta intima. Transmission and reflection spectroscopy was performed using integrating spears in 10 specimens of human cadaver aorta between 270 and 2500 nm. We concluded that no intrinsic chromaphore was present that would consistently differentiate atheroma from normal tissue and that the intense absorption in the ultraviolet and infra-red regions provides the best propect for localized plaque ablation while minimizing thermal damage to surrounding vessel wall.